The present invention relates to a casting chamber for a die casting machine, of which the cylindrical inner surface constitutes a sliding surface for a pressure piston, with a feed opening for molten casting material.
Such casting chambers are known and include an oil or water-cooling apparatus by which excessive heat, introduced along with the molten casting material, can be led away and the casting chamber can be maintained at a constant working temperature, so that heat-deformation of the casting chamber remains as small as possible. Further, in the OL DE 44 21 598 a casting chamber has been described in which a half shell providing the feed opening is interchangeably mounted on the casting machine for various uses of the casting machine. In another example embodiment, the region of the casting chamber directly opposite the feed opening, where the greatest wear occurs, has an exchangeable ceramic insert.
The object of the invention is to provide a casting chamber which does not require an oil or water cooled apparatus, without increasing the danger of heat deformation. Further, in the event of wear occurring on the sliding surface for the pressure piston, it is not necessary to replace the entire casting chamber. Further there is the possibility of casting with higher casting chamber temperatures.
In accordance with the invention, the stated object is attained, with a casting chamber of the kind described above, by installing in the casting chamber jacket along its entire length or a part of the length, an interchangeable inner jacket which provides the sliding surface for the pressure piston, the inner jacket being pressed against the casting chamber jacket by means of a pressure apparatus. Where the inner jacket extends over the entire length, the heat distribution is uniform over the entire length. However it is possible that an inner jacket extending over only a part of the length would suffice. By means of the pressure apparatus there is attained a good contact between the inner jacket and the steel casting chamber jacket, so that heat in the latter can be further conducted away.